Water Management in Horticultural Crops (1+1)

Introduction

• Attempts have been made from time to time to use meteorological parameters, which are the major factors demanding atmospheric moisture, for estimating the evapotranspiration and consumptive use for controlling irrigation.
  
• For this purpose, empirical formulae using different meteorological parameters have been developed. Penman (1948), Thornthwaite (1948), Blaney–Criddle (1950) and Christiansen (1968) developed formulae for estimating potential evapotranspiration and then used the estimated evapotranspiration for scheduling irrigation by water budget method.
  
• The daily evapotranspiration loss is deducted from the soil water reserve in root zone soil after irrigation and a balance is worked out. When the balance show that the soil water is depleted to a predetermined level, say, the lower level of optimum soil water regime, irrigation is applied to replenish the water lost through evapotranspiration.
  
• The adoption of empirical formulae for irrigation control demands the knowledge of water holding capacity of soil and a continuous record of rainfall and other meteorological parameters. This approach of scheduling irrigation to crops is complicated for an ordinary farmer.